Machine for cutting diamonds



Aug, 12 1924.

E. F. A. C. LEPERRE MACHINE FOR CUTTING DIAMONDS Filed Aug. 15

1921 2 Sheets-$heet 1 Aug. 12 1924.

' 11,5U4fi5 E. F. A. C. LEPERRE MACHINE FOR CUTTING DIAMONDS Filed Aug. 15, 1921 2 Sheets-Sheat 3 for": j M mg f cam' m4, g f ww Patented Aug. l2, lQZ lt MACHINE FOB CUTTING DIAMONDS.

Application filed August 15, 1921.

To all whom it may concern:

Be it known that I, EMILE FERDINAND ADELIN Crmnnns LnrERRn, a subject of the King of the Belgians. residing at 46 Rue du Champ, Berchem, Antwerp, Belgium, have invented new and useful Improvements lielating to Machines for Cutting Diamonds, of which the following is a specification.

This invention relates to cutting machines for precious stones and has for its object to provide an improved device for advancing the dop carrier electrically with hand control and for automatically withdrawing the dop carrier after a predetermined period of engagement with the grinding tool.

According to the invention a grinding machine for precious stones includes a dop carrier mounted upon. a solenoid casing movable through mechanical connections actuated by its core to advance the dop towards the grinding tool, a circuit breaking device adjustable to operate after the dop has been advanced to a predetermined point serving to deenergize the solenoid and allow the dop to be withdrawn automatically.

In the drawing is illustrated by way of example a form of construction of the subject of the inventionf Figure 1 shows a vertical longitudinal section through a part of a grinding machine constructed according to this invention.

Figure 2 is an end view and section of the solenoid and associated parts.

Figure 3 is a diagram of the electric circuit and,

Figure 4; shows a plan of the contact bridge of the circuit in the open position.

The stone supporting apparatus or dop l is provided at its base with a shortened conical extension 2 which fits into a corre sponding recess in a hollow cylinder 3 enclosing a solenoid -1- of which the core carries at its inner end two levers 6 The tree ends of the levers 6 are provided with rollers 7 which bear upon an oscillating lever 8. The fulcrurns of the levers 6 are formed by rollers 7 disposed within the interior of the hollow cylinder and bearing against the core 5. The oscillating lever B is ad justable in height and for this purpose is carried by a lever 9 which is mounted on a pivot 11 in the holder 10. The adjustment is efl'ected by means of a screw 12 terminating in a ball 18 above which engages a forked spring 14 secured to the lever 9 by a screw Serial No. 492,496.

15. In order to draw the hollow cylinder 3 backwardly when a current no longer flows through the winding of the solenoid it is connected to the holder 10 by a spiral spring 16.

When a current passes through the windiug of the solenoid 4t the core 5' is attracted. The levers 6 act by means of their supporting points (rollers 7) upon the oscillating lever 8 and by their bearing points (rollers 7) against the underside of the cylinder so that the whole core 5, cylinder 3 with coil i and dop 1 are raised and the stone to be operated upon is brought into contact with the grinding tool.

When the current is interrupted the core 5 is no longer attracted and the solenoid and associated parts are pulled downvmrds by the action of the spring 16.

To the cylinder 3 is connected the push slider 17 of a dial indicator 19 of a coinparator of which the pointer 18' operated by the slider 17, indicates the movement of the parts 1, 3, at and 5 together.

The comparator is of the type generally known in industry.

The fore part of the solenoid lis connected with the mass of the machine; the end of that solenoid gets to the push-slider l7 and influences thus the body of the coin parator and thence the pointer 18.

The pointer 18 is provided with a contact 20 and the dial, plate with a contact 21 at the zero-point. pointer form a switch which breaks the circuit when the contacts 20 and 21 come into contact. The dial plate is adjustable, i. e. the zero point may be brought into a suitable position.

In series with the electroniagnet 41- is electro-magnet 22 01 which the windi considerably shorter than that of the nnw net 4- and is tor example 1/100 thereof so that the attractive pull of the electro-magnet 22 is very weak and does not create any sparks at the switch 20. 21.

The mass oi the comparator insu ated from the cylinder 3 and connectet with one of the ends of the solenoid 22. The contact bridge 21 being placed on the isolatingmatter dial 19 is thus insulated from the mass of the comparator and united to the second extremity of the solenoid 22 and at the same time to the contact point 23.

hen the core of the electro-magnet 22 is magnetized it attracts the iron plate 24 The dial plate and the position.

in such a manner that a bridge 24:- provided thereon connects the two contact points 23 and 23. When the magnetization ceases the bridge is raised under the action of a spring 25.

In order to prevent any jerk of the dia mond against the grinding tool when the solenoid 4 is energized, the core 5 of the latter is connected by a cord 28 to a hand lever- 26, supported by a spring 27, which keeps the 3 1, 28 taut, and prevents the lever 26 from falling out of convenient reach of the, operator. The hand lever 26 enables the operator to control the feed of the dop towards the tool, i

The, method of operation of the machine is as follows By turning the dial plate of the indicator the. ero point thereof is brought to a distance away from the contact point 20 of the pointer corresponding to the thickness to be; ground oil the stone. Then, whilst holding the, hand lever 26, the circuit is closed by depressing the bridge 2a which connects together the twocontacts 23, 23. The current passes through the two electro magnets arranged in series and energizes these so thatthe plate 24- with the br dge 24 attracted thereto remains in its lowered Whilst the. core 5 is being attracted, the lever 26 is gradually released until-the stone comes into contact with the grinding tool. As the grinding operation proceeds, the pointer 18 indicates the feed and when the pointer comes into contact with the contact point 21 at the zero point of the dial plate the electr0-magnet 22 is short circuited Thecontact bridge2 will then no longer be. attracted and rises under the action of the. spring- 25 breaking the circuit by leaving the contacts 23, 23. As

the core 5 is nowno longer attracted the cylinder; 3 With the dop 1' is pulled away from the grinding tool by the spring 16.

l. A machine for cutting precious stones comprising a dop carrier, a solenoid core, an energizing coil surrounding said core, a casing surrounding said coil and supporting said d'opcarrier, a pair of levers pivoted to said core, means for supporting the free endsof said levers, rollers on said coil casing bearing on said levers, a feed indicating device, means operated by said device for breaking the solenoid circuit and a spring for withdrawing said casing and dop carrier.

2. A machine for cutting precious stones comprising a dop carrier, a solenoid core,

a coil casing surrounding said core, means operated by movement of said core for advancing said casing and dop carrier, a feed indicating device, a fixed contact on said device, an electro-magnet in series with the solenoid coil, a bridge in the solenoid circuit controlled by said electro-magnet and a spring for withdrawing said casing and dop carrier.

8. A machine for cutting precious stones comprising a dop carrier, a solenoid core, an energizing coil surrounding said core, a casing surrounding said coil and supporting said dop carrier, a pair of lovers pivoted to said core, rollers on the free ends of said levers, an oscillating lever supporting said rollers, rollers on said coil casing bearing on said levers a feed indicating device, a fixed contact on said device, a moving contact on said device, an elcctro-magnet in series with the solenoid coil, a bridge in the solenoid circuit controlled by said electro-magnet and a spring for withdrawing said casing and dop carrier.

i. A machine for cutting precious stones comprising a dop carrier, a solenoid core, an energizing coil surroundingsaid core, a casing surrounding said coil and supporting said dop carrier, pair ol levers pivoted to said core, rollers on the free ends of said levers, an oscillating lever support ing said rollers, rollers on said coil casing bearing on said levers a feed indicating device, a fixed contact on said device, a moving contact on said device, an electro-inagnet in series ith the solenoid coil, :1 bridge in the solenoid circuit controlled by said clcctromagnet, a spring tending to retain said bridge in open position and a spring for withdrawing said casing and dop carrier.

5. A machine for cutting precious stones comprising a dop carrier, a solenoid core, an energizing coil surrounding said core, a casing surrounding said coil and supporting said dop carrier, :1 pair of levers pivoted to said core, rollers on the free ends of said levers, an oscillating lever supporting said rollers, rollers on said coil casing bearing on said levers, a feed indicating device, a fixed contact on said device, a mov ing contact on said device, an electro-magnet in series with the solenoid coil, a bridge in the solenoid circuit controlled by said elcctro-magnct, a spring tending to retain said bridge in open position, :1 pivoted hand lever, a connection between said band lever and the solenoid core and a spring for with drawing said casing and dop carrier.

EMILE FERDINAND ADELIN CHARLES LEPERRE. 

